Subject: [PATCH v2] PCI: rockchip-dwc: Potential error pointer dereference in probe

From: Dan Carpenter <[email-masked]>
Date: Fri, 13 Aug 2021 17:26:48 +0300

If devm_regulator_get_optional() returns -ENODEV then it would lead
to an error pointer dereference on the next line and in the error
handling code.

Fixes: e1229e884e19 ("PCI: rockchip-dwc: Add Rockchip RK356X host controller driver")
Signed-off-by: Dan Carpenter <[email-masked]>
---
v2: The -ENODEV from devm_regulator_get_optional() has to be handled
    specially.

 drivers/pci/controller/dwc/pcie-dw-rockchip.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
index 20cef2e06f66..c9b341e55cbb 100644
--- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
+++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
@@ -224,15 +224,17 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
 
 	/* DON'T MOVE ME: must be enable before PHY init */
 	rockchip->vpcie3v3 = devm_regulator_get_optional(dev, "vpcie3v3");
-	if (IS_ERR(rockchip->vpcie3v3))
+	if (IS_ERR(rockchip->vpcie3v3)) {
 		if (PTR_ERR(rockchip->vpcie3v3) != -ENODEV)
 			return dev_err_probe(dev, PTR_ERR(rockchip->vpcie3v3),
 					"failed to get vpcie3v3 regulator\n");
-
-	ret = regulator_enable(rockchip->vpcie3v3);
-	if (ret) {
-		dev_err(dev, "failed to enable vpcie3v3 regulator\n");
-		return ret;
+		rockchip->vpcie3v3 = NULL;
+	} else {
+		ret = regulator_enable(rockchip->vpcie3v3);
+		if (ret) {
+			dev_err(dev, "failed to enable vpcie3v3 regulator\n");
+			return ret;
+		}
 	}
 
 	ret = rockchip_pcie_phy_init(rockchip);
@@ -255,7 +257,8 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
 deinit_phy:
 	rockchip_pcie_phy_deinit(rockchip);
 disable_regulator:
-	regulator_disable(rockchip->vpcie3v3);
+	if (rockchip->vpcie3v3)
+		regulator_disable(rockchip->vpcie3v3);
 
 	return ret;
 }
-- 
2.20.1

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